2004 expedition eddie bauer wire harness

Hello everyone! Long time reader, first time posting! I have a 2004 Expy Eddie Bauer w/the premium sound system (6 cd changer and sub) I am looking to upgrade the factory headunit to something newer/better. I have been looking at some Nav Units from Pionner, and will be installing it myself. I see that all these head units require splicing into the VSS wire. So here is where I need help: 1. If I DO NOT have the factory NAV, will the VSS wire be in the radio harness? If so, can anyone provide a diagram/pics to aid me? 2. If it IS NOT in the factory harness, where would I find the VSS wire? 3. Anyone on here with a 2004 Expedition that can share their install experience? Thanks in advance everyone! Any and all help will be greatly appreciated!

Hey thanks for the response. Could you provide a pic or what the module looks like? I see it mentions wiper motor... I have read about those special speed sensing wipers... I'm not sure if I have one, how could I tell if the VSS wire would be there?

I have no photographs of the PCM.  If you can take a picture of the passenger side firewall of your vehicle, under the hood, I am sure we can point it out for you.